Triatoma carcavalloi is considered a rare Chagas disease vector often collected inside domiciles in Rio Grande do Sul State. In this Brazilian state, T. carcavalloi has been collected in the same ecotope (rock piles) with two other species (T. rubrovaria and T. circummaculata), with which it also shares morphological characteristics. Previous morphological studies placed T. carcavalloi in the same species complex ("infestans complex") and subcomplex ("rubrovaria subcomplex") as T. rubrovaria, whereas T. circummaculata was placed in the "circummaculata complex." The phylogeny of a group composed of 16 species of triatomines was reevaluated with the inclusion of T. carcavalloi by Bayesian analysis using mtDNA sequences of subunits 12S and 16S of the ribosomal RNA, and the cytochrome oxidase I (COI) genes. The phenotypic relationship among T. carcavalloi and related triatomines was also inferred from morphometrics. Phylogenetic results indicate that T. carcavalloi is a sister species of T. rubrovaria, and both were recovered as closely related to T. circummaculata. Morphometric studies confirmed the closeness among T. carcavalloi, T. rubrovaria, and T. circummaculata, prompting the placement of the latter species in the "infestans complex" and "rubrovaria subcomplex."

Introduction:Triatoma carcavalloi is a wild species that is found in sympatry with Triatoma rubrovaria and Triatoma circummaculata, which are vectors of Trypanosoma cruzi currently found in rural areas of Rio Grande do Sul, Brazil. Methods: Fertility was assessed and to determine the incubation period, the eggs were observed until hatching. The first meal was offered to 1 st stage nymphs. The intermolt period was also determined. The number of blood meals was quantified at each nymphal stage and the resistance to fasting as the period between ecdysis and death. Mortality was assessed and longevity was determined by recording the time that elapsed from molting to the adult stage and until death. The developmental cycle was assessed by recording the length in days of each stage from molting to adult hood. Results: The average incubation period was 22.7 days. The average first meal occurred 3.1 days after hatching. The 5 th stage nymph to adult intermolting period was the longest at 193.4 days. The average number of feedings during nymphal development was 13.4. The resistance to fasting assay indicated that the 3 rd , 4 th and 5 th stage nymphs presented higher resistance than did adults. The highest mortality rate was observed in the 3 rd stage nymphs (22.2%). The average length of adult survival was 25.6 weeks, and the average total life cycle lasted 503.4 days. Conclusions:This study is the first report on the biology of T. carcavalloi that fed on mice. The presented findings expand the bionomic knowledge of these species.

Histological and ultrastrucutural alterations in the midgut of Aedes albopictus larvae infected with Bacillus thuringiensis var. israelensis (Bti) were observed by light and transmission electron microscopy (TEM). Two formulations of Bti were used: granulated and powder, with 0.2% active ingredient in 90 larvae of Ae. albopictus distributed in three containers containing 30 larvae each (one control group and two test groups). The midgut epithelium of the control group presented flattened and elongated cells with mace-shape with a narrow base. Midgut epithelium cells' surface was convex and had a large circular nucleus located in the median-apical portion of the cell. These cells also presented a basal lamina with a small accumulation of extracellular fibrous matrix, thus characterizing a basal membrane, with a muscle layer and a peritoneal membrane more externally. After Bti ingestion, the larvae stopped/slowed their natural movements down in 5 min. After 30 min approximately, the swimming movements stopped completely. Internally, the intestinal cells showed a disorganization of the basal processes, dilatation and fragmentation of the rough endoplasmic reticulum, with intense cytoplasmic vacuolization. There were concentric dense laminas accumulated in the cytoplasm, and these residual membranous bodies were seen greatly increased in size after 60 min. Mitochondria, fragments of rough endoplasmic reticulum and other remainder organelles were surrounded and segregated from the cytoplasm by exocytosis. This article reports the histopathological alterations in the midgut of Ae. albopictus after infection with Bti and contributes to a better understanding of the mode of action of this bacterial strain used as bioinsecticide against mosquito larvae.